I'm facing a strange issue... I think I could use some help

I installed the new version of OTRS (3.1) to use the new functionality which permit to fetch mails from a particular IMAP folder. I configure my regular mail address for OTRS, all is working fine -> All mail from inbox fetched. I configure then OTRS to fetch mails from a particular folder -> OTRS displays "finished" but no mail fetched (neither on inbox nor on the specified folder)... (it is a company mail : outlook, exchange, etc)
I made the same procedure with a gmail account and all is working fine...
I'm a bit confused here... Do you have any clues?
Thank you in advance
